```rust,no_run
/// This is a doc comment.
-#[doc = " This is a doc comment."]
+#[doc = r" This is a doc comment."]
# fn f() {}
```
-(Note the leading space in the attribute version.)
+(Note the leading space and the raw string literal in the attribute version.)
In most cases, `///` is easier to use than `#[doc]`. One case where the latter is easier is
when generating documentation in macros; the `collapse-docs` pass will combine multiple